curl\_unescape(3) Library Functions Manual curl\_unescape(3)

# [NAME](#NAME)

curl\_unescape - URL decode a string

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
char *curl_unescape(const char *input, int length);
```

# [DESCRIPTION](#DESCRIPTION)

Deprecated. Use [*curl\_easy\_unescape(3)*](/man/os/curl/curl_easy_unescape.3) instead.

This function converts the URL encoded string **input** to a "plain string" and return that as a new allocated string. All input characters that are URL encoded (%XX where XX is a two-digit hexadecimal number) are converted to their plain text versions. Although not constrained by its type, the returned data may not be altered.

If the **length** argument is set to 0, [*curl\_unescape(3)*](/man/os/curl/curl_unescape.3) calls strlen() on **input** to find out the size.

You must [*curl\_free(3)*](/man/os/curl/curl_free.3) the returned string when you are done with it.

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#EXAMPLE)

```
int main(void)
{


  CURL *curl = curl_easy_init();


  if(curl) {


    char *decoded = curl_unescape("%63%75%72%6c", 12);


    if(decoded) {


      /* do not assume printf() works on the decoded data */


      printf("Decoded: ");


      /* ... */


      curl_free(decoded);


    }


  }
}
```

# [DEPRECATED](#DEPRECATED)

Since 7.15.4, [*curl\_easy\_unescape(3)*](/man/os/curl/curl_easy_unescape.3) should be used. This function might be removed in a future release.

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.1

# [RETURN VALUE](#RETURN_VALUE)

A pointer to a null-terminated string or NULL if it failed.

# [SEE ALSO](#SEE_ALSO)

**RFC**2396, [**curl\_easy\_escape**(3)](/man/os/curl/curl_easy_escape.3), [**curl\_easy\_unescape**(3)](/man/os/curl/curl_easy_unescape.3), [**curl\_free**(3)](/man/os/curl/curl_free.3)

2026-09-24 libcurl

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Document: curl_unescape(3) from curl 8.22.0-r3 (Chainguard OS)
Source: https://github.com/curl/curl.git