Index for Section 3

Alphabetical listing for S

Bottom of page

string(3)
NAME
  strcat, strcmp, strcpy, strdup - Perform operations on strings

SYNOPSIS
  #include <string.h>

  char *strcat(
	  char *s1,
	  const char *s2 );

  int strcmp(
	  const char *s1,
	  const char *s2 );

  char *strcpy(
	  char *s1,
	  const char *s2 );

  char *strdup(
	  const char *s1 );

LIBRARY
  Standard C Library (libc)

  System V Library (libsys5.a, libsys5.so)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  strcat(), strcmp(), strcpy():	 XSH4.2

  strdup():  XSH4.2

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  s1  In strcat(), specifies the destination string for appending; in
      strcmp(), specifies the first of two strings to compare; in strcpy(),
      specifies the destination string for the copying; and in strdup(),
      specifies the string to be duplicated.

  s2  In strcat(), specifies the string to be appended to s1; in strcmp(),
      specifies the second of two strings to compare; and in strcpy(),
      specifies the source string for the copying.

				     Note

       [Tru64 UNIX]  If you pass a NULL pointer as one of the const char * or
       char * parameters of a string manipulation function, the function
       generates a segmentation violation. To avoid the segmentation
       violation and cause the function to return zero, change the NULL
       pointer treatment for the process before issuing the call to the
       string manipulation function, as follows:

	1.  Include the system header file sys/uswitch.h.

	2.  Call the uswitch function, as described in the uswitch(2)
	    reference page.

  The following program illustrates this procedure:

       #include <stdio.h>
       #include <sys/types.h>
       #include <sys/uswitch.h>

       main()
       {
	       size_t  retval;
	       int     uswitch_val;

	       uswitch_val = uswitch(USC_GET,0);
	       uswitch(USC_SET, uswitch_val | USW_NULLP);
	       retval = strdup(NULL);

DESCRIPTION
  The strcat() function appends a copy of the string pointed to by the s2
  parameter (including the terminating null byte) to the end of the string
  pointed to by the s1 parameter. The initial byte of s2 overwrites the null
  byte at the end of the string pointed to by s1. When operating on
  overlapping strings, the behavior of this function is unreliable.

  The strcmp() function compares the string pointed to by the s1 parameter to
  the string pointed to by the s2 parameter. The sign of a nonzero value
  returned by strcmp() is determined by the sign of the difference between
  the values of the first pair of bytes (both interpreted as unsigned char)
  that differ in the two compared objects.

  The strcmp() function compares strings based on the machine collating
  order. It does not use the locale-dependent sorting order.  Use the
  strcoll() or wcscoll() functions for locale-dependent sorting.

  The strcpy() function copies the string pointed to by the s2 parameter
  (including the terminating null byte) to the location pointed to by the s1
  parameter.  When operating on overlapping strings, the behavior of this
  function is unreliable.

  The strdup() function returns a pointer to a new string that is an exact
  duplicate of the string pointed to by the s1 parameter. The malloc()
  function is used to allocate space for the new string.

RETURN VALUES
  On successful completion, the strcat(), strcpy(), and strdup() functions
  return a pointer to the resulting string. Otherwise, these functions return
  a null pointer.  The strdup() function sets errno to indicate the error.

  On successful completion, the strcmp() function returns an integer whose
  value is greater than, equal to, or less than 0 (zero), according to
  whether the s1 string is greater than, equal to, or less than the s2
  string.

ERRORS
  If the strdup() function fails, errno may be set to the following value:

  [ENOMEM]
      Insufficient storage space is available.

SEE ALSO
  Functions: malloc(3), memccpy(3), setlocale(3), strchr(3), strcoll(3),
  strlen(3), strncasecmp(3), strncat(3), strncmp(3), strncpy(3), strpbrk(3),
  strspn(3), strtok(3), strstr(3), strxfrm(3), swab(3), uswitch(2),
  wcscat(3), wcscmp(3), wcscpy(3)

  Standards: standards(5)

Index for Section 3

Alphabetical listing for S

Top of page