strchr

From cppreference.com
< c‎ | string‎ | byte
Defined in header <string.h>
char *strchr( const char *str, int ch );
(1)
/*QChar*/ *strchr( /*QChar*/ *str, int ch );
(2) (since C23)
1) Finds the first occurrence of ch (after conversion to char as if by (char)ch) in the null-terminated byte string pointed to by str (each character interpreted as unsigned char). The terminating null character is considered to be a part of the string and can be found when searching for '\0'.
2) Type-generic function equivalent to (1). Let T be an unqualified character object type.
  • If str is of type const T*, the return type is const char*.
  • Otherwise, if str is of type T*, the return type is char*.
  • Otherwise, the behavior is undefined.
If a macro definition of each of these generic functions is suppressed to access an actual function (e.g. if (strchr) or a function pointer is used), the actual function declaration (1) becomes visible.

The behavior is undefined if str is not a pointer to a null-terminated byte string.

Parameters

str - pointer to the null-terminated byte string to be analyzed
ch - character to search for

Return value

Pointer to the found character in str, or null pointer if no such character is found.

Example

#include <stdio.h>
#include <string.h>
 
int main(void)
{
  const char *str = "Try not. Do, or do not. There is no try.";
  char target = 'T';
  const char *result = str;
 
  while((result = strchr(result, target)) != NULL) {
    printf("Found '%c' starting at '%s'\n", target, result);
    ++result; // Increment result, otherwise we'll find target at the same location
  }
}

Output:

Found 'T' starting at 'Try not. Do, or do not. There is no try.'
Found 'T' starting at 'There is no try.'

References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.24.5.2 The strchr function (p: 367-368)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.21.5.2 The strchr function (p: 330)
  • C89/C90 standard (ISO/IEC 9899:1990):
  • 4.11.5.2 The strchr function

See also

searches an array for the first occurrence of a character
(function)
finds the last occurrence of a character
(function)
finds the first location of any character in one string, in another string
(function)