[Libjpeg-devel-6x] Check for SOI Symbol function

[Klin I. <ga...@ya...>]

Hello,

i'm new to libjpeg, and want to know how the error  JMESSAGE(JERR_NO_SOI, "Not a JPEG file: starts with 0x%02x 0x%02x") is generated. 
I found the JFIF marker. So, isn't there a SOI marker too?

Thank You
Axel