Returns the address of the first occurrence of a given character
    in a null-terminated string.

    Format

      #include  <string.h>

      char *strchr  (const char *str, int character);

1 - Function Variants

    The strchr function has variants named _strchr32 and _strchr64
    for use with 32-bit and 64-bit pointer sizes, respectively.

2 - Arguments

 str

    A pointer to a null-terminated character string.

 character

    An object of type int.

3 - Description

    This function returns the address of the first occurrence of a
    given character in a null-terminated string. The terminating null
    character is considered to be part of the string.

    Compare with strrchr, which returns the address of the last
    occurrence of a given character in a null-terminated string.

4 - Return Values

    x                  The address of the first occurrence of the
                       specified character.
    NULL               Indicates that the character does not occur in
                       the string.

5 - Example

        #include <stdio.h>
        #include <string.h>

        main()
        {

            static char s1buf[] = "abcdefghijkl lkjihgfedcba";

            int i;

            char *status;

        /*  This program checks the strchr function by incrementally   */
        /*  going through a string that ascends to the middle and then */
        /*  descends towards the end.                                  */

            for (i = 0; s1buf[i] != '\0' && s1buf[i] != ' '; i++) {
                status = strchr(s1buf, s1buf[i]);

        /* Check for pointer to leftmost character - test 1.           */

                if (status != &s1buf[i])
                    printf("error in strchr");
            }
        }