---
name: "curl_escape"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/curl_escape"
---

# curl\_escape(3)

URL encode a string

## NAME

curl\_escape - URL encode a string

## SYNOPSIS

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

## DESCRIPTION

Obsolete function. Use *[curl\_easy\_escape(3)](/curl_easy_escape/3.md)* 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)](/curl_escape/3.md)* uses strlen() on **string** to find out the size.

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

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
int main(void)
{
  char *output = curl_escape("data to convert", 15);
  if(output) {
    printf("Encoded: %s\n", output);
    curl_free(output);
  }
}
```

## HISTORY

Since 7.15.4, *[curl\_easy\_escape(3)](/curl_easy_escape/3.md)* should be used. This function might be removed in a future release.

## AVAILABILITY

Added in curl 7.1

## RETURN VALUE

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

## SEE ALSO

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