diff --git a/appveyor.yml b/appveyor.yml
index 9397d627aa..daed228e32 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -40,7 +40,7 @@ build_script:
   - if "%BUILD_TYPE%" == "cmake" if "%platform%" == "x64" SET VS_FULL=%VS_VERSION% Win64
   - if "%BUILD_TYPE%" == "cmake" if "%platform%" == "x86" SET VS_FULL=%VS_VERSION%
   - if "%BUILD_TYPE%" == "cmake" echo "%VS_FULL%"
-  - if "%BUILD_TYPE%" == "cmake" cmake -G "%VS_FULL%" . -DSELFTEST=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE=../bin -DBUILD_LIBPROJ_SHARED=ON
+  - if "%BUILD_TYPE%" == "cmake" cmake -G "%VS_FULL%" . -DSELFTEST=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE=../bin -DBUILD_LIBPROJ_SHARED=ON -D_CRT_SECURE_NO_WARNINGS -DCMAKE_C_FLAGS="/W3 /WX"
   - if "%BUILD_TYPE%" == "cmake" cmake --build . --config Release
 
 test_script:
diff --git a/src/PJ_horner.c b/src/PJ_horner.c
index 3dde29c8a4..4ee2e78abf 100644
--- a/src/PJ_horner.c
+++ b/src/PJ_horner.c
@@ -134,7 +134,7 @@ static void horner_free (HORNER *h) {
 
 static HORNER *horner_alloc (size_t order, int complex_polynomia) {
     /* size_t is unsigned, so we need not check for order > 0 */
-    int n = horner_number_of_coefficients(order);
+    int n = (int)horner_number_of_coefficients(order);
     int polynomia_ok = 0;
     HORNER *h = horner_calloc (1, sizeof (HORNER));
 
@@ -142,8 +142,8 @@ static HORNER *horner_alloc (size_t order, int complex_polynomia) {
         return 0;
 
     if (complex_polynomia)
-        n = 2*order + 2;
-    h->order = order;
+        n = 2*(int)order + 2;
+    h->order = (int)order;
     h->coefs = n;
 
     if (complex_polynomia) {
diff --git a/src/PJ_pipeline.c b/src/PJ_pipeline.c
index 0dae0e595c..e61954a091 100644
--- a/src/PJ_pipeline.c
+++ b/src/PJ_pipeline.c
@@ -309,7 +309,7 @@ static PJ *pj_create_pipeline (PJ *P, size_t steps) {
     if (0==P->opaque->pipeline)
         return 0;
 
-    P->opaque->steps = steps;
+    P->opaque->steps = (int)steps;
 
     P->opaque->reverse_step =  pj_calloc (steps + 2, sizeof(int));
     if (0==P->opaque->reverse_step)
@@ -369,7 +369,7 @@ PJ *PROJECTION(pipeline) {
     if (0==P->opaque)
         return 0;
 
-    argc = argc_params (P->params);
+    argc = (int)argc_params (P->params);
     P->opaque->argv = argv = argv_params (P->params, argc);
     if (0==argv)
         return pipeline_freeup (P, ENOMEM);
diff --git a/src/nad_init.c b/src/nad_init.c
index 3b35ea639b..14fa5226f0 100644
--- a/src/nad_init.c
+++ b/src/nad_init.c
@@ -134,7 +134,7 @@ struct CTABLE *nad_ctable_init( projCtx ctx, PAFile fid )
     }
     
     /* trim white space and newlines off id */
-    for( id_end = strlen(ct->id)-1; id_end > 0; id_end-- )
+    for( id_end = (int)strlen(ct->id)-1; id_end > 0; id_end-- )
     {
         if( ct->id[id_end] == '\n' || ct->id[id_end] == ' ' )
             ct->id[id_end] = '\0';
@@ -181,7 +181,7 @@ int nad_ctable2_load( projCtx ctx, struct CTABLE *ct, PAFile fid )
 
     if( !IS_LSB )
     {
-        swap_words( ct->cvs, 4, a_size * 2 );
+        swap_words( ct->cvs, 4, (int)a_size * 2 );
     }
 
     return 1;
@@ -243,7 +243,7 @@ struct CTABLE *nad_ctable2_init( projCtx ctx, PAFile fid )
     }
     
     /* trim white space and newlines off id */
-    for( id_end = strlen(ct->id)-1; id_end > 0; id_end-- )
+    for( id_end = (int)strlen(ct->id)-1; id_end > 0; id_end-- )
     {
         if( ct->id[id_end] == '\n' || ct->id[id_end] == ' ' )
             ct->id[id_end] = '\0';
diff --git a/src/pj_init.c b/src/pj_init.c
index 24aece8461..62901fdf0f 100644
--- a/src/pj_init.c
+++ b/src/pj_init.c
@@ -73,7 +73,7 @@ static const char *fill_buffer(pj_read_state *state, const char *last_char)
 /*      Move the existing data to the start of the buffer.              */
 /* -------------------------------------------------------------------- */
     memmove(state->buffer, last_char, char_remaining);
-    state->buffer_filled = char_remaining;
+    state->buffer_filled = (int)char_remaining;
     last_char = state->buffer;
 
 /* -------------------------------------------------------------------- */
@@ -116,7 +116,7 @@ static const char *fill_buffer(pj_read_state *state, const char *last_char)
         *w++ = *r++;
     }
     *w = 0;
-    state->buffer_filled += (bytes_read - (r-w));
+    state->buffer_filled += (int)(bytes_read - (r-w));
 
     return last_char;
 }
@@ -139,7 +139,7 @@ get_opt(projCtx ctx, paralist **start, PAFile fid, char *name, paralist *next,
     if(found_def)
         *found_def = 0;
 
-    len = strlen(name);
+    len = (int)strlen(name);
     *sword = 't';
 
     if (0==next_char)
diff --git a/src/pj_open_lib.c b/src/pj_open_lib.c
index 0a2e7fecac..d5ad2549e4 100644
--- a/src/pj_open_lib.c
+++ b/src/pj_open_lib.c
@@ -113,7 +113,7 @@ pj_open_lib(projCtx ctx, const char *name, const char *mode) {
     if (*name == '~' && strchr(dir_chars,name[1]) )
         if ((sysname = getenv("HOME")) != NULL) {
             (void)strcpy(fname, sysname);
-            fname[n = strlen(fname)] = DIR_CHAR;
+            fname[n = (int)strlen(fname)] = DIR_CHAR;
             fname[++n] = '\0';
             (void)strcpy(fname+n, name + 1);
             sysname = fname;
@@ -134,7 +134,7 @@ pj_open_lib(projCtx ctx, const char *name, const char *mode) {
     /* or is environment PROJ_LIB defined */
     else if ((sysname = getenv("PROJ_LIB")) || (sysname = proj_lib_name)) {
         (void)strcpy(fname, sysname);
-        fname[n = strlen(fname)] = DIR_CHAR;
+        fname[n = (int)strlen(fname)] = DIR_CHAR;
         fname[++n] = '\0';
         (void)strcpy(fname+n, name);
         sysname = fname;
diff --git a/src/pj_param.c b/src/pj_param.c
index 24c2354e31..93f5cf53e2 100644
--- a/src/pj_param.c
+++ b/src/pj_param.c
@@ -45,7 +45,7 @@ pj_param(projCtx ctx, paralist *pl, const char *opt) {
 
 	type = *opt++;
 	/* simple linear lookup */
-	l = strlen(opt);
+	l = (int)strlen(opt);
 	while (pl && !(!strncmp(pl->param, opt, l) &&
 	  (!pl->param[l] || pl->param[l] == '=')))
 		pl = pl->next;
diff --git a/src/pj_pr_list.c b/src/pj_pr_list.c
index 95aab4a08a..5ccfbe5b9a 100644
--- a/src/pj_pr_list.c
+++ b/src/pj_pr_list.c
@@ -11,7 +11,7 @@ pr_list(PJ *P, int not_used) {
 	(void)putchar('#');
 	for (t = P->params; t; t = t->next)
 		if ((!not_used && t->used) || (not_used && !t->used)) {
-			l = strlen(t->param) + 1;
+			l = (int)strlen(t->param) + 1;
 			if (n + l > LINE_LEN) {
 				(void)fputs("\n#", stdout);
 				n = 2;
@@ -71,7 +71,7 @@ char *pj_get_def( PJ *P, int options )
             continue;
 
         /* grow the resulting string if needed */
-        l = strlen(t->param) + 1;
+        l = (int)strlen(t->param) + 1;
         if( strlen(definition) + l + 5 > def_max )
         {
             char *def2;