CURLOPT\_CONV\_FROM\_NETWORK\_FUNCTION(3) Library Functions Manual CURLOPT\_CONV\_FROM\_NETWORK\_FUNCTION(3)

# [NAME](#NAME)

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

# [SYNOPSIS](#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](#DESCRIPTION)

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

Applies to non-ASCII platforms. [*curl\_version\_info(3)*](/man/os/curl/curl_version_info.3) 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)*](/man/os/curl/CURLOPT_CONV_FROM_NETWORK_FUNCTION.3) 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](#DEFAULT)

NULL

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#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](#DEPRECATED)

Not available and deprecated since 7.82.0.

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

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.15.4

# [RETURN VALUE](#RETURN_VALUE)

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

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

# [SEE ALSO](#SEE_ALSO)

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

2026-10-31 libcurl

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Document: CURLOPT_CONV_FROM_NETWORK_FUNCTION(3) from curl 8.23.0-r3 (Chainguard OS)
Source: https://github.com/curl/curl.git