intToStr sends 0x0 characters as part of the AT command.

[stephane-chazelas]

When using

echo test | gsmsendsms -C "$service_center" -b 19200 -d "$device" "$mobile_number"

I get a

ME/TA error 'invalid PDU mode parameter' (code 304)

Running it under strace, I see that the ERROR 304 comes in response to:

write(3, "AT+CMGS=18\0\r", 12)    = 12

Note the spurious NUL character there.

This diff:

diff --git a/gsmlib/gsm_util.cc b/gsmlib/gsm_util.cc
index 373592c..f054929 100644
--- a/gsmlib/gsm_util.cc
+++ b/gsmlib/gsm_util.cc
@@ -164,7 +164,7 @@ bool gsmlib::hexToBuf(const std::string &hexString, unsigned char *buf)
 std::string gsmlib::intToStr(int i)
 {
   std::ostringstream os;
-  os << i << std::ends;
+  os << i;
   return os.str();
 }
 

makes that character and the error go away. I don't know enough of C++ to know why that std:ends was there in the first place.

That's tested with the current git HEAD (cd5442d) on Debian unstable (libstdc++6:amd64 7.2.0-16), though the problem was initially seen on Debian jessie (libstdc++6:amd64 4.9.2-10, libgsmme1c2a:amd64 1.10+20120414.gita5e5ae9a-0.2)

It's possible that it is a regression as I didn't get the error on Debian squeeze with the same GSM modem.