what to do to avoid this error: invalid conversion from 'void*' to 'char*' [-fpermissive] in qt ?

[Qt embedded developer]

Below line give error when i convert my c program in qt
pFileBuffer = malloc(st.st_size);
// error: invalid conversion from 'void*' to 'char*' [-fpermissive]

my c code is :

      int nSourceFile;
        struct stat st;
        long n;
        int nSeconds;
        unsigned int nResult;
        char *pFileBuffer;

        stat(SOURCE_FILE,&st);
        printf("source file '%s', size = %d\n\r",  SOURCE_FILE, st.st_size);
        if((nSourceFile= open(SOURCE_FILE,O_RDONLY))<  0)
        {
            printf("can not open data classes source file \n\r");
            exit(1);
        }

        pFileBuffer = malloc(st.st_size);
        
        if (!pFileBuffer)
        exit(1);
        
        read(nSourceFile, pFileBuffer, st.st_size);
        ::close(nSourceFile);
        qDebug()<<pMainApp.ObjSettings.ObjFuelCheck.gauge_execute_fs(pMainApp.ObjSettings.ObjFuelCheck.nI2CId, pFileBuffer);

        free(pFileBuffer);

[Qt embedded developer]

By writing below type casting solved this error
pFileBuffer =(char *) malloc(st.st_size);