diff --git a/src/algorithms/libs/rtklib/rtklib_rtkcmn.cc b/src/algorithms/libs/rtklib/rtklib_rtkcmn.cc
index 95d08a32a..e21af5d08 100644
--- a/src/algorithms/libs/rtklib/rtklib_rtkcmn.cc
+++ b/src/algorithms/libs/rtklib/rtklib_rtkcmn.cc
@@ -229,7 +229,7 @@ void fatalerr(const char *format, ...)
     char msg[1024];
     va_list ap;
     va_start(ap, format);
-    vsnprintf(msg, 1024, format, ap);
+    vsnprintf(msg, sizeof(msg), format, ap);
     va_end(ap);
     fprintf(stderr, "%s", msg);
     exit(-9);
@@ -4084,7 +4084,7 @@ void trace(int level, const char *format, ...)
     va_list ap;
     char buffer[256];
     va_start(ap, format);
-    vsnprintf(buffer, 256, format, ap);
+    vsnprintf(buffer, sizeof(buffer), format, ap);
     va_end(ap);
     std::string str(buffer);
     VLOG(level) << "RTKLIB TRACE[" << level << "]:" << str;
diff --git a/src/algorithms/libs/rtklib/rtklib_rtkpos.cc b/src/algorithms/libs/rtklib/rtklib_rtkpos.cc
index cd8ce552b..8c31aec6b 100644
--- a/src/algorithms/libs/rtklib/rtklib_rtkpos.cc
+++ b/src/algorithms/libs/rtklib/rtklib_rtkpos.cc
@@ -504,7 +504,7 @@ void errmsg(rtk_t *rtk, const char *format, ...)
     time2str(rtk->sol.time, tstr, 2);
     n = std::snprintf(buff, sizeof(buff), "%s: ", tstr + 11);
     va_start(ap, format);
-    n += vsnprintf(buff + n, 256, format, ap);
+    n += vsnprintf(buff + n, sizeof(buff) - n, format, ap);
     va_end(ap);
     n = n < MAXERRMSG - rtk->neb ? n : MAXERRMSG - rtk->neb;
     memcpy(rtk->errbuf + rtk->neb, buff, n);