Loadrunner Function lr_save_var to convert C variable into loadrunner parameter

Loadrunner

lr_save_var:

This loadrunner function saves the defined bytes of a content from a one variable to the other.

Syntax:

lr_save_var(source parameter, value length(bytes), option, destination parameter)

C Program:

In our below C program we are going to see how the file content stored in a c variable is converted to a loadrunner parameter. (comments highlighted in RED matters)

//#include <stdio.h>
#define SEEK_SET 0 /* beginning of file. */
#define SEEK_CUR 1 /* current position. */
#define SEEK_END 2   /* end of file */


Action()
{
 long infile; // file pointer
 char *buffer; // buffer to read file contents into
 char *filename = "test.txt"; // file to read
 int fileLen; // file size
 int bytesRead; // bytes read from file
 //
 // open the file
 infile = fopen(filename, "rb");
 if (!infile) {
    lr_error_message("Unable to open file %s", filename);
    return;
 }


 // get the file length
 fseek(infile, 0, SEEK_END);
 fileLen=ftell(infile);
 fseek(infile, 0, SEEK_SET);
 lr_log_message("File length is: %9d bytes.", fileLen);


 // Allocate memory for buffer to read file
 buffer=(char *)malloc(fileLen+1);
 if (!buffer) {
    lr_error_message("Could not malloc %10d bytes", fileLen+1);
    fclose(infile);
    return;
 }


 // Read file contents into buffer & saves the file length in bytes to bytesRead 
 bytesRead = fread(buffer, 1, fileLen, infile);
 if (bytesRead != fileLen)
 {
    lr_error_message("File length is %10d bytes but only read %10d bytes", fileLen, bytesRead);
 }
 else
 {
    lr_log_message("Successfully read %9d bytes from file: ", bytesRead);
 }
 fclose(infile);


 // Save the C variable 'buffer' to a loadrunner parameter 'fileDataParameter'
 lr_save_var( buffer, bytesRead, 0, "fileDataParameter");
 free(buffer);
 lr_log_message("File contents: %s", lr_eval_string("{fileDataParameter}"));
}


In the above code

Source parameter -- File contents are stored in the c variable buffer.
Value length -- File length in bytes is saved in the c variable bytesRead.
Option -- By default set option to 0.
Destination Parameter -- File contents to be copied to the Loadrunner Parameter fileDataParameter.