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

# [NAME](#NAME)

curl\_escape - URL encode a string

# [SYNOPSIS](#SYNOPSIS)

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

# [DESCRIPTION](#DESCRIPTION)

Obsolete function. Use [*curl\_easy\_escape(3)*](/man/os/curl/curl_easy_escape.3) instead.

This function converts the given input **string** to a URL encoded string and return that as a new allocated string. All input characters that are not a-z, A-Z or 0-9 are converted to their "URL escaped" version (**%NN** where **NN** is a two-digit hexadecimal number). Although not constrained by its type, the returned string may not be altered.

If the **length** argument is set to 0, [*curl\_escape(3)*](/man/os/curl/curl_escape.3) uses strlen() on **string** 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)
{


  char *output = curl_escape("data to convert", 15);


  if(output) {


    printf("Encoded: %s\n", output);


    curl_free(output);


  }
}
```

# [HISTORY](#HISTORY)

Since 7.15.4, [*curl\_easy\_escape(3)*](/man/os/curl/curl_easy_escape.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)

[**curl\_free**(3)](/man/os/curl/curl_free.3), [**curl\_unescape**(3)](/man/os/curl/curl_unescape.3)

2026-10-14 libcurl

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Document: curl_escape(3) from curl 8.23.0-r0 (Chainguard OS)
Source: https://github.com/curl/curl.git