Categories of Intrinsic Functions

Generic intrinsic functions can be divided into categories, as shown in the following table:

Categories of Intrinsic Functions

Category  Subcategory  Description 
Numeric  Computation  Elemental functions that perform type conversions or simple numeric operations: ABS, AIMAG, AINT, AMAX0, AMIN0, ANINT, CEILING, CMPLX, CONJG, DBLE, DCMPLX, DFLOAT, DIM, DNUM, DPROD, DREAL, FLOAT, FLOOR, IFIX, ILEN, IMAG, INT, INUM, JNUM, MAX, MAX1, MIN, MIN1, MOD, MODULO, NINT, QCMPLX, QEXT, QFLOAT, QNUM, QREAL, RAN, REAL, RNUM, SIGN, SNGL, ZEXT 
  Manipulation1  Elemental functions that return values related to the components of the model values associated with the actual value of the argument: EXPONENT, FRACTION, NEAREST, RRSPACING, SCALE, SET_EXPONENT, SPACING 
  Inquiry1  Functions that return scalar values from the models associated with the type and kind parameters of their arguments2: DIGITS, EPSILON, HUGE, MAXEXPONENT, MINEXPONENT, PRECISION, RADIX, RANGE, SIZEOF, TINY 
  Transformational  Functions that perform vector and matrix multiplication: DOT_PRODUCT, MATMUL 
  System  Functions that return information about a process or processor: MCLOCK, SECNDS 
Kind type    Functions that return kind type parameters: KIND, SELECTED_INT_KIND, SELECTED_REAL_KIND 
Mathematical    Functions that perform mathematical operations: ACOS, ACOSD, ACOSH, ASIN, ASIND, ASINH, ATAN, ATAN2, ATAN2D, ATAND, ATANH, COS, COSD, COSH, COTAN, COTAND, EXP, LOG, LOG10, SIN, SIND, SINH, SQRT, TAN, TAND, TANH 
Bit  Manipulation  Elemental functions that perform single-bit processing, logical and shift operations, and allow bit subfields to be referenced: AND, BTEST, DSHIFTL, DSHIFTR, IAND, IBCHNG, IBCLR, IBITS, IBSET, IEOR, IOR, ISHA, ISHC, ISHFT, ISHFTC, ISHL, IXOR, LSHIFT, NOT, OR, RSHIFT, SHIFTL, SHIFTR, XOR 
  Inquiry  Function that lets you determine parameter s (the bit size) in the bit model3: BIT_SIZE 
  Representation  Functions that return information on bit representation of integers: LEADZ, POPCNT, POPPAR, TRAILZ 
Character  Comparison  Elemental functions that make a lexical comparison of the character-string arguments and return a default logical result: LGE, LGT, LLE, LLT 
  Conversion  Elemental functions that take character arguments and return integer, ASCII, or character values4: ACHAR, CHAR, IACHAR, ICHAR 
  String handling  Functions that perform operations on character strings, return lengths of arguments, and search for certain arguments: ADJUSTL, ADJUSTR, INDEX, LEN_TRIM, REPEAT, SCAN, TRIM, VERIFY 
  Inquiry  Functions that return the length of an argument or information about command-line arguments: COMMAND_ARGUMENT_COUNT, IARG, IARGC, LEN, NARGS, NUMARG 
Array  Construction  Functions that construct new arrays from the elements of existing array: MERGE, PACK, SPREAD, UNPACK 
  Inquiry  Functions that let you determine if an array argument is allocated, and return the size or shape of an array, and the lower and upper bounds of subscripts along each dimension: ALLOCATED, LBOUND, SHAPE, SIZE, UBOUND 
  Location  Transformational functions that find the geometric locations of the maximum and minimum values of an array: MAXLOC, MINLOC 
  Manipulation  Transformational functions that shift an array, transpose an array, or change the shape of an array: CSHIFT, EOSHIFT, RESHAPE, TRANSPOSE 
  Reduction  Transformational functions that perform operations on arrays. The functions "reduce" elements of a whole array to produce a scalar result, or they can be applied to a specific dimension of an array to produce a result array with a rank reduced by one: ALL, ANY, COUNT, MAXVAL, MINVAL, PRODUCT 
Miscellaneous    Functions that do the following:
  • Check for pointer association (ASSOCIATED)
  • Return an address (BADDRESS)
  • Return the size of a level of the memory cache (CACHESIZE)
  • Check for end-of-file (EOF)
  • Return error functions (ERF and ERFC)
  • Return the class of a floating-point argument (FP_CLASS)
  • Return the INTEGER KIND that will hold an address (INT_PTR_KIND)
  • Test for Not-a-Number values (ISNAN)
  • Return the internal address of a storage item (LOC)
  • Return a logical value of an argument (LOGICAL)
  • Allocate memory (MALLOC)
  • Return the upper 64 bits of a 128-bit unsigned result (MULT_HIGH)
  • Return the upper 64 bits of a 128-bit signed result (MULT_HIGH_SIGNED)
  • Return a disassociated pointer (NULL)
  • Check for argument presence (PRESENT)
  • Convert a bit pattern (TRANSFER)
  • Check for end-of-file condition (IS_IOSTAT_END)
  • Check for end-of-record condition (IS_IOSTAT_EOR)
1 All of the numeric manipulation, and many of the numeric inquiry functions are defined by the model sets for integers and reals.
2 The value of the argument does not have to be defined.
3 For more information on bit functions, see Bit functions.
4 The Intel® Fortran processor character set is ASCII, so ACHAR = CHAR and IACHAR = ICHAR.

The following table summarizes the generic intrinsic functions and indicates whether they are elemental, inquiry, or transformational functions. Optional arguments are shown within square brackets.

Some intrinsic functions are specific with no generic association. These functions are listed below.

Summary of Generic Intrinsic Functions

Generic Function  Class Value Returned 
ABS (A)  E  The absolute value of an argument 
ACHAR (I)  E  The character in the specified position of the ASCII character set 
ACOS (X)  E  The arccosine (in radians) of the argument 
ACOSD (X)  E  The arccosine (in degrees) of the argument 
ACOSH (X)  E  The hyperbolic arccosine of the argument 
ADJUSTL (STRING)  E  The specified string with leading blanks removed and placed at the end of the string 
ADJUSTR (STRING)  E  The specified string with trailing blanks removed and placed at the beginning of the string 
AIMAG (Z)  E  The imaginary part of a complex argument 
AINT (A [,KIND])  E  A real value truncated to a whole number 
ALL (MASK [,DIM])  T  .TRUE. if all elements of the masked array are true 
ALLOCATED (ARRAY)  I  The allocation status of the argument array 
AMAX0 (A1, A2 [, A3,...])  E  The maximum value in a list of integers (returned as a real value) 
AMIN0 (A1, A2 [, A3,...])  E  The minimum value in a list of integers (returned as a real value) 
AND (I, J)  E  See IAND 
ANINT (A [, KIND])  E  A real value rounded to a whole number 
ANY (MASK [, DIM])  T  .TRUE. if any elements of the masked array are true 
ASIN (X)  E  The arcsine (in radians) of the argument 
ASIND (X)  E  The arcsine (in degrees) of the argument 
ASINH (X)  E  The hyperbolic arcsine of the argument 
ASSOCIATED (POINTER [,TARGET])  I  .TRUE. if the pointer argument is associated or the pointer is associated with the specified target 
ATAN (X)  E  The arctangent (in radians) of the argument 
ATAN2 (Y, X)  E  The arctangent (in radians) of the arguments 
ATAN2D (Y, X)  E  The arctangent (in degrees) of the arguments 
ATAND (X)  E  The arctangent (in degrees) of the argument 
ATANH (X)  E  The hyperbolic arctangent of the argument 
BADDRESS (X)  I  The address of the argument 
BIT_SIZE (I)  I  The number of bits (s) in the bit model 
BTEST (I, POS)  E  .TRUE. if the specified position of argument I is one 
CEILING (A [,KIND])  E  The smallest integer greater than or equal to the argument value 
CHAR (I [,KIND])  E  The character in the specified position of the processor character set 
COMMAND_ARGUMENT_COUNT ()  I  The number of command arguments 
CONJG (Z)  E  The conjugate of a complex number 
COS (X)  E  The cosine of the argument, which is in radians 
COSD (X)  E  The cosine of the argument, which is in degrees 
COSH (X)  E  The hyperbolic cosine of the argument 
COTAN (X)  E  The cotangent of the argument, which is in radians 
COTAND (X)  E  The cotangent of the argument, which is in degrees 
COUNT (MASK [,DIM] [,KIND])  T  The number of .TRUE. elements in the argument array 
CSHIFT (ARRAY, SHIFT [,DIM])  T  An array that has the elements of the argument array circularly shifted 
DBLE (A)  E  The corresponding double precision value of the argument 
DFLOAT (A)  E  The corresponding double precision value of the integer argument 
DIGITS (X)  I  The number of significant digits in the model for the argument 
DIM (X, Y)  E  The positive difference between the two arguments  
DOT_PRODUCT (VECTOR_A, VECTOR_B)  T  The dot product of two rank-one arrays (also called a vector multiply function) 
DREAL (A)  E  The corresponding double-precision value of the double complex argument 
DSHIFTL (ILEFT, IRIGHT, ISHIFT)  E  The upper (leftmost) 64 bits of a left-shifted 128-bit integer 
DSHIFTR (ILEFT, IRIGHT, ISHIFT)  E  The lower (rightmost) 64 bits of a right-shifted 128-bit integer 
EOF (A)  I  .TRUE. or .FALSE. depending on whether a file is beyond the end-of-file record 
EOSHIFT (ARRAY, SHIFT [,BOUNDARY] [,DIM])  T  An array that has the elements of the argument array end-off shifted 
EPSILON (X)  I  The number that is almost negligible when compared to one 
ERF (X)  E  The error function of an argument  
ERFC (X)  E  The complementary error function of an argument  
EXP (X)  E  The exponential ex for the argument x  
EXPONENT (X)  E  The value of the exponent part of a real argument 
FLOAT (X)  E  The corresponding real value of the integer argument 
FLOOR (A [,KIND])  E  The largest integer less than or equal to the argument value 
FP_CLASS (X)  E  The class of the IEEE floating-point argument 
FRACTION (X)  E  The fractional part of a real argument 
HUGE (X)  I  The largest number in the model for the argument 
IACHAR (C)  E  The position of the specified character in the ASCII character set 
IADDR (X)  E  See BADDRESS 
IAND (I, J)  E  The logical AND of the two arguments 
IBCLR (I, POS)  E  The specified position of argument I cleared (set to zero) 
IBCHNG (I, POS)  E  The reversed value of a specified bit 
IBITS (I, POS, LEN)  E  The specified substring of bits of argument I 
IBSET (I, POS)  E  The specified bit in argument I set to one 
ICHAR (C [, KIND])  E  The position of the specified character in the processor character set 
IEOR (I, J)  E  The logical exclusive OR of the corresponding bit arguments 
IFIX (X)  E  The corresponding integer value of the real argument rounded as if it were an implied conversion in an assignment 
ILEN (I)  I  The length (in bits) in the two's complement representation of an integer 
IMAG (Z)  E  See AIMAG 
INDEX (STRING, SUBSTRING [, BACK] [,KIND])  E  The position of the specified substring in a character expression 
INT (A [, KIND])  E  The corresponding integer value (truncated) of the argument 
IOR (I, J)  E  The logical inclusive OR of the corresponding bit arguments 
IS_IOSTAT_END (I)  E  .TRUE. if an end-of-file condition exists. 
IS_IOSTAT_EOR (I)  E  .TRUE. if an end-of-record condition exists. 
ISHA (I, SHIFT)  E  Argument I shifted left or right by a specified number of bits 
ISHC (I, SHIFT)  E  Argument I rotated left or right by a specified number of bits 
ISHFT (I, SHIFT)  E  The logical end-off shift of the bits in argument I 
ISHFTC (I, SHIFT [,SIZE])  E  The logical circular shift of the bits in argument I 
ISHL (I, SHIFT)  E  Argument I logically shifted left or right by a specified number of bits 
ISNAN (X)  E  Tests for Not-a-Number (NaN) values 
IXOR (I, J)  E  See IEOR 
KIND (X)   I  The kind type parameter of the argument 
LBOUND (ARRAY [,DIM] [,KIND])  I  The lower bounds of an array (or one of its dimensions) 
LEADZ (I)  E  The number of leading zero bits in an integer 
LEN (STRING [,KIND])  I  The length (number of characters) of the argument character string 
LEN_TRIM (STRING [,KIND])  E  The length of the specified string without trailing blanks 
LGE (STRING_A, STRING_B)  E  A logical value determined by a > or = comparison of the arguments 
LGT (STRING_A, STRING_ B)  E  A logical value determined by a > comparison of the arguments 
LLE (STRING_A, STRING_B)  E  A logical value determined by a < or = comparison of the arguments 
LLT (STRING_A, STRING_B)  E  A logical value determined by a < comparison of the arguments 
LOC (A)  I  The internal address of the argument. 
LOG (X)  E  The natural logarithm of the argument 
LOG10 (X)  E  The common logarithm (base 10) of the argument 
LOGICAL (L [,KIND])   E  The logical value of the argument converted to a logical of type KIND 
LSHIFT (I, POSITIVE_SHIFT) 1  E  See ISHFT 
MATMUL (MATRIX_A, MATRIX_B)  T  The result of matrix multiplication (also called a matrix multiply function) 
MAX (A1, A2 [, A3,...])  E  The maximum value in the set of arguments 
MAX1 (A1, A2 [, A3,...])  E  The maximum value in the set of real arguments (returned as an integer) 
MAXEXPONENT (X)  I  The maximum exponent in the model for the argument 
MAXLOC (ARRAY [,DIM] [,MASK] [,KIND])  T  The rank-one array that has the location of the maximum element in the argument array 
MAXVAL (ARRAY [,DIM] [,MASK])  T  The maximum value of the elements in the argument array 
MERGE (TSOURCE, FSOURCE, MASK)   E  An array that is the combination of two conformable arrays (under a mask) 
MIN (A1, A2 [, A3,...])  E  The minimum value in the set of arguments 
MIN1 (A1, A2 [, A3,...])  E  The minimum value in the set of real arguments (returned as an integer) 
MINEXPONENT (X)  I  The minimum exponent in the model for the argument 
MINLOC (ARRAY [,DIM] [,MASK] [,KIND])  T  The rank-one array that has the location of the minimum element in the argument array 
MINVAL (ARRAY [,DIM] [,MASK])  T  The minimum value of the elements in the argument array 
MOD (A, P)  E  The remainder of the arguments (has the sign of the first argument) 
MODULO (A, P)  E  The modulo of the arguments (has the sign of the second argument) 
NEAREST (X, S)  E  The nearest different machine-representable number in a given direction 
NINT (A [,KIND])  E  A real value rounded to the nearest integer 
NOT (I)  E  The logical complement of the argument 
NULL ([MOLD])  T  A disassociated pointer 
OR (I, J)  E  See IOR 
PACK (ARRAY, MASK [,VECTOR])  T  A packed array of rank one (under a mask) 
POPCNT (I)  E  The number of 1 bits in the integer argument 
POPPAR (I)  E  The parity of the integer argument 
PRECISION (X)  I  The decimal precision (real or complex) of the argument 
PRESENT (A)   I  .TRUE. if an actual argument has been provided for an optional dummy argument 
PRODUCT (ARRAY [,DIM] [,MASK])  T  The product of the elements of the argument array 
QEXT (A)  E  The corresponding REAL(16) precision value of the argument  
QFLOAT (A)  E  The corresponding REAL(16) precision value of the integer argument  
RADIX (X)  I  The base of the model for the argument 
RANGE (X)  I  The decimal exponent range of the model for the argument 
REAL (A [, KIND])  E  The corresponding real value of the argument 
REPEAT (STRING, NCOPIES)   T  The concatenation of zero or more copies of the specified string 
RESHAPE (SOURCE, SHAPE [,PAD] [,ORDER])  T  An array that has a different shape than the argument array, but the same elements 
RRSPACING (X)  E  The reciprocal of the relative spacing near the argument 
RSHIFT (I, NEGATIVE_SHIFT) 2  E  See ISHFT 
SCALE (X, I)  E  The value of the exponent part (of the model for the argument) changed by a specified value 
SCAN (STRING, SET [,BACK] [,KIND])  E  The position of the specified character (or set of characters) within a string 
SELECTED_INT_KIND (R)  T  The integer kind parameter of the argument 
SELECTED_REAL_KIND ([P] [, R])  T  The real kind parameter of the argument; one of the optional arguments must be specified 
SET_EXPONENT (X, I)  E  The value of the exponent part (of the model for the argument) set to a specified value 
SHAPE (SOURCE [,KIND])  I  The shape (rank and extents) of an array or scalar 
SHIFTL (IVALUE, ISHIFT)  E  Argument IVALUE shifted left by a specified number of bits  
SHIFTR (IVALUE, ISHIFT)  E  Argument IVALUE shifted right by a specified number of bits  
SIGN (A, B)  E  A value with the sign transferred from its second argument 
SIN (X)  E  The sine of the argument, which is in radians 
SIND (X)  E  The sine of the argument, which is in degreess 
SINH (X)  E  The hyperbolic sine of the argument 
SIZE (ARRAY [,DIM] [,KIND])  I  The size (total number of elements) of the argument array (or one of its dimensions) 
SIZEOF (X)  I  The bytes of storage used by the argument 
SNGL (X)  E  The corresponding real value of the argument 
SPACING (X)  E  The value of the absolute spacing of model numbers near the argument 
SPREAD (SOURCE, DIM, NCOPIES)   T  A replicated array that has an added dimension 
SQRT (X)  E  The square root of the argument 
SUM (ARRAY [,DIM] [,MASK])  T  The sum of the elements of the argument array 
TAN (X)  E  The tangent of the argument, which is in radians 
TAND (X)  E  The tangent of the argument, which is in degrees 
TANH (X)  E  The hyperbolic tangent of the argument 
TINY (X)  I  The smallest positive number in the model for the argument 
TRAILZ (I)  E  The number of trailing zero bits in an integer 
TRANSFER (SOURCE, MOLD [,SIZE])   T  The bit pattern of SOURCE converted to the type and kind parameters of MOLD 
TRANSPOSE (MATRIX)  T  The matrix transpose for the rank-two argument array 
TRIM (STRING)   T  The argument with trailing blanks removed 
UBOUND (ARRAY [,DIM] [,KIND])  I  The upper bounds of an array (or one of its dimensions) 
UNPACK (VECTOR, MASK, FIELD)   T  An array (under a mask) unpacked from a rank-one array 
VERIFY (STRING, SET [,BACK] [,KIND])  E  The position of the first character in a string that does not appear in the given set of characters 
XOR (I, J)  E  See IEOR 
ZEXT (X [,KIND])  E  A zero-extended value of the argument 
Key to Classes

E-Elemental
I-Inquiry
T-Transformational

1 Or LSHFT.
2 Or RSHFT.

The following table lists specific functions that have no generic function associated with them and indicates whether they are elemental, nonelemental, or inquiry functions. Optional arguments are shown within square brackets.

Specific Functions with No Generic Association

Generic Function  Class Value Returned 
CACHESIZE (N)1  I  The size of a level of the memory cache  
CMPLX (X [,Y] [,KIND])  E  The corresponding complex value of the argument 
DCMPLX (X, Y)  E  The corresponding double complex value of the argument 
DNUM (I)  E  The corresponding double-precision value of a character string  
DPROD (X, Y)  E  The double-precision product of two real arguments 
DREAL (A)  E  The corresponding double-precision value of the double-complex argument
IARG ( )  I  See IARGC
IARGC ( )  I  The index of the last command-line argument
INUM (I)  E  The corresponding INTEGER(2) value of a character string  
JNUM (I)  E  The corresponding INTEGER(4) value of a character string  
MALLOC (I)  E  The starting address for the block of memory allocated 
MCLOCK ( )  I  The sum of the current process’s user time and the user and system time of all its child processes 
MULT_HIGH (I, J)1  E  The upper (leftmost) 64 bits of the 128-bit unsigned result 
MULT_HIGH_SIGNED (I, J)1  E  The upper (leftmost) 64 bits of the 128-bit signed result 
NARGS ( )  I  The total number of command-line arguments, including the command
NUMARG ( )  I  See IARGC
QCMPLX (X, Y)  E  The corresponding COMPLEX(16) value of the argument  
QNUM (I)  E  The corresponding REAL(16) value of a character string  
QREAL (A)  E  The corresponding REAL(16) value of the real part of a COMPLEX(16) argument  
RAN (I)  N  The next number from a sequence of pseudorandom numbers (uniformly distributed in the range 0 to 1) 
RNUM (I)  E  The corresponding REAL(4) value of a character string  
SECNDS (X)  E  The system time of day (or elapsed time) as a floating-point value in seconds 
Key to Classes

E-Elemental
I-Inquiry
N-Nonelemental
1 i64 only