---
name: "CURLOPT_CONV_FROM_NETWORK_FUNCTION"
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/CURLOPT_CONV_FROM_NETWORK_FUNCTION"
---

# CURLOPT\_CONV\_FROM\_NETWORK\_FUNCTION(3)

convert data from network to host encoding

## NAME

CURLOPT\_CONV\_FROM\_NETWORK\_FUNCTION - convert data from network to host encoding

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode conv_callback(char *ptr, size_t length);
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CONV_FROM_NETWORK_FUNCTION,
                          conv_callback);
```

## DESCRIPTION

Pass a pointer to your callback function, which should match the prototype shown above.

Applies to non-ASCII platforms. *[curl\_version\_info(3)](/curl_version_info/3.md)* returns the **CURL\_VERSION\_CONV** feature bit set if this option is provided.

The data to be converted is in a buffer pointed to by the *ptr* parameter. The amount of data to convert is indicated by the *length* parameter. The converted data overlays the input data in the buffer pointed to by the ptr parameter. *CURLE\_OK* must be returned upon successful conversion. A CURLcode return value defined by curl.h, such as *CURLE\_CONV\_FAILED*, should be returned if an error was encountered.

*[CURLOPT\_CONV\_FROM\_NETWORK\_FUNCTION(3)](/CURLOPT_CONV_FROM_NETWORK_FUNCTION/3.md)* converts to host encoding from the network encoding. It is used when commands or ASCII data are received over the network.

If you set a callback pointer to NULL, or do not set it at all, the built-in libcurl iconv functions are used. If HAVE\_ICONV was not defined when libcurl was built, and no callback has been established, the conversion returns the **CURLE\_CONV\_REQD** error code.

If **HAVE\_ICONV** is defined, **CURL\_ICONV\_CODESET\_OF\_HOST** must also be defined. For example:

```
#define CURL_ICONV_CODESET_OF_HOST "IBM-1047"
```

The iconv code in libcurl defaults the network and UTF8 codeset names as follows:

```
#define CURL_ICONV_CODESET_OF_NETWORK "ISO8859-1"
#define CURL_ICONV_CODESET_FOR_UTF8  "UTF-8"
```

You need to override these definitions if they are different on your system.

## DEFAULT

NULL

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
static CURLcode my_conv_from_ascii_to_ebcdic(char *buffer, size_t length)
{
  int rc = 0;
  /* in-place convert 'buffer' from ASCII to EBCDIC */
  if(rc == 0) {
    /* success */
    return CURLE_OK;
  }
  else {
    return CURLE_CONV_FAILED;
  }
}
int main(void)
{
  CURL *curl = curl_easy_init();
  /* use platform-specific functions for codeset conversions */
  curl_easy_setopt(curl, CURLOPT_CONV_FROM_NETWORK_FUNCTION,
                   my_conv_from_ascii_to_ebcdic);
}
```

## DEPRECATED

Not available and deprecated since 7.82.0.

Available only if **CURL\_DOES\_CONVERSIONS** was defined when libcurl was built.

## AVAILABILITY

Added in curl 7.15.4

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_CONV\_FROM\_UTF8\_FUNCTION**(3)](/CURLOPT_CONV_FROM_UTF8_FUNCTION/3.md), [**CURLOPT\_CONV\_TO\_NETWORK\_FUNCTION**(3)](/CURLOPT_CONV_TO_NETWORK_FUNCTION/3.md)