PHP gmp_export() Function

As of my last update in September 2021, there is no built-in gmp_export() function in PHP. However, PHP does provide the gmp_export() function, which allows you to export a GMP (GNU Multiple Precision) number as a binary string.

Here’s the syntax of the gmp_export() function:

string gmp_export ( GMP $num [, int $word_size = 1 [, int $options = GMP_MSW_FIRST | GMP_NATIVE_ENDIAN ]] )

Parameters:

• $num: The GMP number to be exported.
• $word_size (optional): The number of bytes per word. Default is 1.
• $options (optional): A bitmask of options. Default is GMP_MSW_FIRST | GMP_NATIVE_ENDIAN. The available options are:
• GMP_MSW_FIRST: Most significant word first (big-endian). If not set, least significant word first (little-endian) is used.
• GMP_NATIVE_ENDIAN: The endianness of the system is used. If not set, big-endian is used.

Return value:

• A binary string containing the exported representation of the GMP number.

Here’s an example of using gmp_export():

$number = gmp_init('1234567890');

$exportedData = gmp_export($number);

echo bin2hex($exportedData); // Output: 499602d2

In this example, the GMP number 1234567890 is exported as a binary string, and the bin2hex() function is used to display the hexadecimal representation of the binary string.

Keep in mind that the GMP extension needs to be enabled in your PHP configuration to use this function. Additionally, please note that the availability of functions may change in newer PHP versions, so always refer to the PHP manual for the specific version you are using.