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 - testing 8.17.0~rc2-1
 - unstable 8.17.0~rc3-1
 
| curl_easy_unescape(3) | Library Functions Manual | curl_easy_unescape(3) | 
NAME¶
curl_easy_unescape - URL decode a string
SYNOPSIS¶
#include <curl/curl.h> char *curl_easy_unescape(CURL *curl, const char *input,
int inlength, int *outlength);
DESCRIPTION¶
This function converts the URL encoded string input to a "plain string" and returns that in an allocated memory area. All input characters that are URL encoded (%XX where XX is a two-digit hexadecimal number) are converted to their binary versions.
If the length argument is set to 0 (zero), curl_easy_unescape(3) uses strlen() on input to find out the size.
If outlength is non-NULL, the function writes the length of the returned string in the integer it points to. This allows proper handling even for strings containing %00. Since this is a pointer to an int type, it can only return a value up to INT_MAX so no longer string can be returned in this parameter.
Since 7.82.0, the curl parameter is ignored. Prior to that there was per-handle character conversion support for some old operating systems such as TPF, but it was otherwise ignored.
You must curl_free(3) the returned string when you are done with it.
PROTOCOLS¶
This functionality affects all supported protocols
EXAMPLE¶
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    int decodelen;
    char *decoded = curl_easy_unescape(curl, "%63%75%72%6c", 12, &decodelen);
    if(decoded) {
      /* do not assume printf() works on the decoded data */
      printf("Decoded: ");
      /* ... */
      curl_free(decoded);
    }
    curl_easy_cleanup(curl);
  }
}
AVAILABILITY¶
Added in curl 7.15.4
RETURN VALUE¶
A pointer to a null-terminated string or NULL if it failed.
SEE ALSO¶
| 2025-09-20 | libcurl |