c++ - comparing strings when 1 string contains part of the other string -

i using following code compare packetbuffer string,

char packetbuffer[udp_tx_packet_max_size]; !strcmp(packetbuffer, "turn on light")

however how use compare string should packetbuffer = testing1234 , string compared equal "testing", out last 4 digits?

the function looking strstr:

if (strstr(packetbuffer, "testing") != null) {     // packetbuffer contains "testing"     // something... }

note: if need test substring @ start of string can this:

if (strstr(packetbuffer, "testing") == packetbuffer) {     // packetbuffer starts "testing"     // something... }

TSQL