QSORT(3F)

NAME

qsort, qsort64 − quick sort

SYNOPSIS

integer∗4 len, isize
integer∗8 len8, isize8
external compar
integer∗2 compar subroutine qsort (array, len, isize, compar)
subroutine qsort64(array,len8, isize8, compar)

DESCRIPTION

One-dimensional array contains the elements to be sorted. len (or len8) is the number of elements in the array. isize (or isize8) is the size of an element, typically:

4 for integer and real (or 4_8 with qsort64)
8 for double precision or complex (or 8_8 with qsort64)
16 for double complex (or 16_8 with qsort64)
or the length of a character element (in bytes) for character arrays

compar is the name of a user-supplied INTEGER∗2 function that determines the sorting order. This function is called with two arguments that are elements of array. The function must return:

negative if arg1 is considered to precede arg2
zero if arg1 is equivalent to arg2
positive if arg1 is considered to follow arg2

On return, the elements of array are sorted. Use qsort64 in 64-bit environments where the size of the array (or character array element) exceeds 2 Gigabytes and can only be specified with an INTEGER∗8 value.

NOTES

When using qsort64, be sure to specify the element size, isize8, and the array length, len8, as INTEGER∗8 data. Specify INTEGER∗8 constants using the Fortran 90 syntax, for example 8_8, as in:     integer∗8 LENARRAY, ARRAY(large_number)
    integer∗2 ORDER
    external ORDER
    ...
    call qsort64(ARRAY, LENARRAY, 8_8, ORDER)

FILES

libF77.a

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